Perennially ice-covered lakes that are tightly sealed from the atmosphere represent a unique group of polar lakes. In these lakes, the δD-δ¹⁸O evolution of the water column and steady-state conditions are controlled by rates of recharge and freezing at the bottom of the ice cover. We developed a recursive model (FREEZCH9) that takes into account the changing salinity in the water column as a result of freezing and mixes the recharge water to the residual water in well-sealed perennially ice-covered lakes. Our model is tested against datasets from Lake Vostok and is used to assess the δD-δ¹⁸O mass balance of Lake Untersee and evaluate if the lake is in isotopic steady-state. Our FREEZCH9 simulations fit well with the predicted δD-δ¹⁸O values of Lake Vostok’s upper water column and the overlying accreted ice. Simulations with FREEZCH9 also suggests that Lake Untersee is in isotopic steady-state and that its two input sources (i.e., subaqueous terminus melting of the Anuchin Glacier and subglacial meltwater) have similar δD-δ¹⁸O composition. Our modeling demonstrates that Lake Untersee most likely did not receive additional input from surface streams during the last 300–500 years. FREEZCH9 may be also used to determine if any groundwater systems of the McMurdo Dry Valleys are fully or partially recharged by subglacial lakes.

与大气层紧密密封的常年覆冰的湖泊代表了一组独特的极地湖泊。在这些湖泊，δD-δ ¹⁸的O的水柱和稳态条件进化由补给的速率来控制，并在冰盖的底部冷冻。我们开发了一种递归模型（FREEZCH9），该模型考虑了结冰导致水柱中盐度变化的问题，并将补给水与常年密闭的覆冰湖泊中的残留水混合。我们的模型是针对从沃斯托克湖的数据集测试，用来评估δD-δ ¹⁸ Untersee湖Ø物料平衡和评估，如果该湖是同位素稳定状态。我们的FREEZCH9模拟合身与预测δD-δ ^18个东方湖的上部水柱O值的和上覆附着的冰。模拟FREEZCH9还表明，温特塞湖是在同位素稳态和其两个输入源（即，阿努钦冰川和冰下融水的水下末端熔化）具有相似的δD-δ ¹⁸ O的合成物。我们的模型表明，在过去300-500年中，Untersee湖极有可能没有从地表水流中获得额外的输入。FREEZCH9 还可以用来确定麦克默多干旱谷的地下水系统是否被冰河湖完全或部分补给。